Well,I used the Cooper's OS (Original Series) lager can because the bittering hop is already done,& rather neutral to slightly fruity. If the German yeast is a smack pack/activator (wyeast or white labs),so do that In the morning of brew day to give it a few hours to go to work.
Then boil 2.5 gallons of water placing the Haulertau & spault or tetnang hop pellets in hop sacks,tie off ends,& pitch into the boiling water,setting the timer for 15 mins. Drain/remove hop sacks,take the Cooper's can & place in pot of hot water to soften. Remove BK from heat,stir in 3lb bag of plain extra light munton's DME into hop tea till all clumps are dissolved.
Stir in softened cooper's lager can to completely incorporate. Place lid on brew kettle,& allow to steep for 15mins or so while you sanitize the fermenter,etc. Then chill wort in sink of ice water down to about 70F Add to fermenter with enough spring water to make 5.5-6G. I made it to 23L,0r 6.072G,since I use a cooper's micro brew FV. But it is my considered opinion That no more than 22L would be better. But 5G would be a bit much. You don't want to overpower the range of flavor desired in this style. By the way,the new avatar pic is it. Ferment at/close to 70F,but a yeast that can do 66-69 is good too. I made a 1 1/2 cup starter with 1/4C of the DME for 3.5 hours that worked fine,since the yeast was old. It took 3 weeks to go from 1.044OG down to 1.012FG. 4.8%ABV to style.